The statements in this section merely provide background information related to the present disclosure. Accordingly, such statements are not intended to constitute an admission of prior art.
Known powertrain systems are configured to transfer torque from a torque-generative device through a transmission device to an output member coupled to a driveline. Some powertrain systems may be configured to transfer torque originating from multiple torque-generative devices through a multi-mode transmission device to an output member coupled to a driveline. Such powertrain systems include hybrid powertrain systems and extended-range electric vehicle systems. Control systems for operating such powertrain systems control the torque-generative devices and apply selected torque transfer elements in the transmission to transfer torque in response to operator-commanded output torque requests, taking into account fuel economy, emissions, driveability, and other factors. Exemplary torque-generative devices include internal combustion engines and non-combustion torque machines. The non-combustion torque machines may include electric machines that operate as motors or generators to generate torque input to the transmission in combination with or independently of torque input from the internal combustion engine. The torque machines may react torque, i.e., transform vehicle kinetic energy transferred through the vehicle driveline to electrical energy that is storable in an electrical energy storage device in what is referred to as a regenerative operation. A control system monitors inputs from the vehicle and the operator and provides operational control of the powertrain, including controlling an engine on/off state, controlling a transmission operating state, controlling the torque-generative devices, and regulating electrical power flow between the electrical energy storage device and the electric machines to manage transmission operation including torque and rotational speed.
Control of a powertrain system includes controlling in a manner that avoids overshoot of electrical power flow, including either electric current or electric voltage from the electrical energy storage device in order to prevent operation which may reduce service life. Known electrical power control systems employ feedback mechanisms to respond to and control operation to minimize overshoot during ongoing operation.